Precast panel mounting system

ABSTRACT

A rigid elongate mounting bracket has an embedment portion and an extension portion. The extension portion has a fastener opening and abutment means. When cast into a precast panel in an appropriate angular orientation adjacent to an edge of a cladding panel, the extension portion projects rearwardly and laterally away from the rear face of the panel end such that the end of the extension portion is disposed at a distance away from the panel&#39;s rear face corresponding to a desired air space, and the abutment means is substantially aligned with the panel&#39;s rear face. Each panel preferably has at least two brackets spaced along its upper edge and two more along its lower edge. A first panel may be mounted to a supporting structure using fasteners driven through the fastener openings of the upper brackets. A second panel may then be positioned with its lower brackets extending downward behind the first panel, with the abutment means of the second panel&#39;s lower brackets engaging the rear face of the first panel, such that the lower end of the second panel is laterally stabilized by the first panel, with a uniform air space being formed between the supporting structure and the panels&#39; rear faces.

FIELD OF THE INVENTION

The present invention relates to precast cladding panels mounted tosupporting structures, and relates in particular to mounting bracketscast into precast panels.

BACKGROUND OF THE INVENTION

Precast panels of various sizes and shapes are widely used as claddingon building walls, serving as components of building envelope systemsintended to prevent infiltration of rain and outside air into thebuilding. Precast cladding panels are commonly made of concrete, but mayalso be made with other cast materials known in the construction field.Concrete cladding panels are common on large structures such as officebuildings, but they are also used on residential housing structures asan alternative to traditional cladding materials such as wood siding andbrick.

Whether installed on large or small buildings, it is desirable forcladding panels to be mounted in such a way that there will be acontinuous air space between the rear (i.e., inner) faces of the panelsand the supporting structure, while at the same time providing reliablestructural support for the panels, both to transfer the vertical weightof the panels to the supporting structure and to provide anchorageagainst lateral forces (such as wind) that may act on the panels.

The purpose of the air space is to provide a passage through which anywater or moisture vapour that gets behind the cladding can be directedaway from the building envelope before it infiltrates other parts of thebuilding. Although caulking or other sealant materials are typicallyused to seal the spaces between cladding panels, the possibility ofmoisture infiltration behind the cladding—as a result of vapourmigration, direct penetration of rainwater (due to sealant deteriorationor other factors), or leakage at roof-to-wall junctures—cannot beentirely eliminated. If such moisture is not removed from the buildingenvelope fairly promptly, it will tend to migrate further into thebuilding, potentially causing a variety of problems that could entailcostly maintenance and repairs and could detract from the building'soverall durability and value. Such problems may include drywall damagedue to moisture absorption, rot and mold in wooden constructioncomponents (e.g., studs and sheathing), corrosion of non-rust-resistantconstruction hardware, and staining on interior building finishes.

When an air space is provided behind the cladding, moisture can rundownward behind the cladding to exit points such as weepholes built intothe cladding system at appropriate locations. The air space alsofacilitates or enhances air circulation behind the cladding, helping toremove moisture vapour before it can condense inside the wall structure,and helping to dry out any wall structure components that may havebecome damp due to moisture infiltration.

The essential problem facing designers of cladding panel support systemsis to provide hangers or brackets that can adequately support weight ofthe panels at a distance away from the face of the supporting structure(i.e., so as to provide the desired air space), without significantlyimpeding the passage of water or water vapour through the air space. Inthis regard, it is particularly desirable to avoid or minimizehanger-to-panel connection details where moisture might become trappedor its vertical flow impeded.

One approach to this problem is to use vertically-oriented hangers castinto the rear faces of the cladding panels, as in Canadian Patent No.2,169,585 issued to Kuelker on Feb. 3, 2004, and similarly in U.S. Pat.No. 6,253,515 issued to Kuelker on Jul. 3, 2001. The hangers used inthis system accomplish the desired objectives of providing goodstructural support without significantly impeding air circulation behindthe panels. It is important, of course, for these hangers to be castinto the panels within fairly close tolerances to facilitate uniformvertical alignment of the panels when they are mounted to a supportingstructure. As well, when using vertically-oriented panel hangers of thisor similar type, it will often be desirable or necessary to control thehorizontal location of the hangers within close tolerances, such as whenit is desired to attach the hangers directly to primary structuralelements (e.g., wall studs) rather than to secondary elements (e.g.,wall sheathing or strapping). It is readily apparent that claddingpanels using vertical hangers of this general type cannot be effectivelyused on unsheathed walls unless the hangers coincide with studlocations, or unless horizontal strapping is installed across the studsat specific vertical intervals (and at additional cost) to receive thehanger fasteners.

It is desirable for concrete cladding panels to be stackable ascompactly as possible to minimize space requirements during storage andshipping. When the panels have embedded hangers that project from thepanels' rear faces, there will always be a space between the stackedpanels equal to at least the thickness of the hangers. Accordingly, thetotal height of a stack of panels may be as much as 20% to 30% greaterthan the sum of the thicknesses of the panels, depending on the relativethickness of the panels and the hanger members. It is desirable,therefore, to have a hanger system that reduces or substantiallyeliminates the space between stacked cladding panels, thus significantlyreducing storage space requirements.

The prior art discloses a number of additional examples of hangersystems for mounting precast cladding panels to vertical supportingstructures, including:

-   -   German Patent Application No. DE 3209746 (Wünsch), filed Mar.        17, 1982;    -   French Patent Application No. 82 14147 (Michelet et al.), filed        Aug. 16, 1982;    -   U.S. Pat. No. 4,553,366 (Guerin), issued Nov. 19, 1985; and    -   European Patent Application No. 89115208.4 (Isele), filed Aug.        18, 1989.        However, none of these prior art systems addresses all of the        problems and desirable features discussed above. Moreover, these        systems are primarily intended for use in the construction of        curtain wall systems or mounting large, heavy concrete cladding        panels on large buildings, and are not conveniently adaptable        for use with comparatively small and light concrete cladding        panels for residential housing structures.

For the foregoing reasons, there is a need for an improved precast panelsupport system that facilitates secure mounting of panels at a uniformdistance away from a vertical supporting structure without introducingsignificant impediments to air flow through the air space thus createdbetween the rear faces of the panels and the supporting structure. Thereis a further need for a panel support system that facilitates accuratepositioning of the hangers in the panels during panel castingoperations, so as to minimize the likelihood of misalignment of themounted panels. There is an additional need for a panel hanger system inwhich lateral location of the hangers in the panels is not critical inorder for the panels to be conveniently and securely anchored tovertical support elements, such as sheathed or unsheathed wall studs. Inaddition, there is a need for a panel hanger system that facilitatesmore compact stacking and storage of panels, with the space betweenstacked panels reduced or eliminated. The present invention is directedto these needs.

BRIEF SUMMARY OF THE INVENTION

In general terms, the present invention is a mounting system for precastcladding panels featuring as its main component a mounting bracket thatcan be cast into a precast cladding panel adjacent to the panel's upperor lower edge. One end or portion of the bracket is intended forembedment in a precast panel, while the other end or portion is intendedto extend or project at an angle both rearwardly and laterally away fromthe rear face of the panel. The mounting bracket is configured such thatwhen cast into a precast panel in an appropriate angular orientation,the end of the extension portion of the bracket will be disposed at adistance away from the rear face of the panel corresponding to thedesired air space. At least one fastener hole is provided in theextension portion of the bracket, for receiving a fastener such as awood screw to attach the panel to a supporting structure. The bracketalso incorporates abutment means which, when the bracket is embedded ina panel as described above, will be substantially in alignment with therear face of the panel.

In a typical application, two or more mounting brackets are cast into apanel adjacent its upper edge, with two or more brackets being cast intothe panel adjacent its lower edge. The upper brackets are used to fastenthe panel to a supporting structure (such as a sheathed stud wall, forinstance, in a residential construction scenario), using screws, spikes,or other suitable fasteners driven through the fastener openings in theupper brackets. The upper brackets thus support the full suspendedweight of the panel, while also positioning the rear face of the panelat a desired distance away from the face of the supporting structure(i.e., corresponding to the desired air space). After a first panel hasbeen thus fastened to the support structure, a second similar panel ispositioned above the first panel, with the lower brackets of the secondpanel extending downward behind the first panel. By virtue of theirinherent configuration and the orientation at which they are cast intothe panel, the lower brackets of the second panel dispose the rear faceof the second panel at the desired distance (i.e., air space thickness)away from the face of the supporting structure. At the same time, theabutment means of the lower brackets of the second panel extend belowthe upper edge of the first panel and engage the rear face of the firstpanel, thus effectively locking the second panel behind the first panel,and preventing the bottom of the second panel from being displacedoutward away from the structure, without any direct connection betweenthe bottom of the second panel and the supporting structure.

Accordingly, in one aspect the present invention is a mounting bracketfor partial embedment in a precast panel having a front face, agenerally planar rear face, an upper edge, and a lower edge, saidbracket comprising:

-   -   (a) a rigid, elongate main body having an outer side, an inner        side, and two longitudinal edges, said main body also defining:        -   a.1 an embedment portion; and        -   a.2 an extension portion contiguous with the embedment            portion, said extension portion having an inner end; and    -   (b) abutment means associated with the outer side of the        extension portion, said abutment means having an outer edge;        wherein when the embedment portion is embedded in a precast        panel such that the extension portion projects from the rear        face of the panel so as to form an obtuse angle between the        inner side of the extension portion and the rear face of the        panel, the outer edge of the abutment means will substantially        coincide with the plane of the rear face of the panel.

In a second aspect, the invention is a precast panel having a frontface, a generally planar rear face, an upper edge, and a lower edge, andfurther having at least two mounting brackets embedded in spaced-apartrelation adjacent a selected one of said upper and lower edges of thepanel, each said mounting bracket comprising:

-   -   (a) a rigid, elongate main body having an outer side, an inner        side, and two longitudinal edges, said main body also defining:        -   a.1 an embedment portion; and        -   a.2 an extension portion contiguous with the embedment            portion, said extension portion having an inner end; and    -   (b) abutment means associated with the outer side of the        extension portion, said abutment means having an outer edge;        wherein the embedment portion of each mounting bracket is        embedded in the panel such that:    -   (c) the extension portion projects from the rear face of the        panel so as to form an obtuse angle between the inner side of        the extension portion and the rear face of the panel;    -   (d) the outer edge of the abutment means substantially coincides        with the plane of the rear face of the panel; and    -   (e) at least a portion of the abutment means is disposed        outboard of the associated panel edge;        and wherein the outer edges of the abutment means of each        bracket is disposed at a substantially uniform distance from the        inner ends of their corresponding extension portions, as        measured perpendicular to the plane of the rear face of the        panel.

In a third aspect, the invention is a forming system that facilitatesaccurate placement of mounting brackets in precast panels to ensure thecreation of a substantially uniform air space behind the panels afterthey are mounted on a supporting structure.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described with reference to theaccompanying figures, in which numerical references denote like parts,and in which:

FIG. 1 is an isometric view of a mounting bracket in accordance with afirst embodiment of the invention.

FIG. 2 is an isometric view of a mounting bracket in accordance with asecond embodiment.

FIG. 3 is an elevation of a precast panel with mounting brackets inaccordance with the invention.

FIG. 4 is an end view of the precast panel of FIG. 3.

FIG. 5 is an elevation of an assembly of precast panels as in FIG. 3,mounted to a vertical supporting structure.

FIG. 6 is an end view of the assembly of FIG. 5.

FIG. 7A is a sectional detail illustrating a typical field connection ofan upper mounting bracket in accordance with the embodiment of FIG. 1.

FIG. 7B is a sectional detail as in FIG. 7A, additionally illustratingthe optional use of an auxiliary fastener.

FIG. 7C is a sectional detail illustrating a typical field connection ofan upper mounting bracket in accordance with the embodiment of FIG. 2.

FIG. 8A is a sectional detail of a horizontal joint between two mountedprecast panels having mounting brackets in accordance with theembodiment of FIG. 1.

FIG. 8B is a sectional detail of a horizontal joint between two mountedprecast panels having mounting brackets in accordance with theembodiment of FIG. 2.

FIG. 9 illustrates a preferred detail for supporting the uppermost panelin a mounted assembly of precast panels in accordance with theinvention.

FIG. 10 illustrates a preferred detail for supporting the lowermostpanel in a mounted assembly of precast panels.

FIG. 11 is an elevation of a precast panel in accordance with theinvention, mounted to an unsheathed wall using a corrugated strappingmember.

FIG. 11A is a cross-section of an exemplary embodiment of the strappingmember shown in FIG. 11.

FIG. 12 illustrates a number of precast panels with mounting brackets inaccordance with the invention, stacked with protective cushioningmaterial disposed between panels.

FIG. 13 is a perspective view of a multi-cell formwork assembly forcasting multiple panels, with pockets for receiving mounting bracketinserts in accordance with the invention.

FIG. 14 illustrates the formwork assembly of FIG. 13, showing mountingbrackets with corresponding inserts positioned in one formwork cell,ready to receive fluid concrete, and showing one formwork cell alreadyfilled with concrete.

FIG. 15 is a sectional detail of a formwork cell filled with concrete asin FIG. 14.

FIG. 16 illustrates a mounting bracket in accordance with a thirdembodiment of the invention, in which the bracket is fashion from wire.

FIG. 17 is a sectional detail of a horizontal joint between two mountedprecast panels having mounting brackets in accordance with theembodiment of FIG. 16.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 1, a rigid, elongate mounting bracket 10 in accordancewith a first embodiment of the invention has an embedment portion 11 anda contiguous extension portion 13. The point of demarcation betweenembedment portion 11 and extension portion 13 is not precisely defined,but will coincide with the rear face of a precast cladding panel inwhich bracket 10 is embedded, as will be described in detail herein.Bracket 10 is preferably fashioned from a corrosion-resistant metal,such as stainless steel, galvanized steel, or plated steel, but othermaterials may also be used provided they have suitable physicalproperties. Persons skilled in the art will appreciate that bracket 10could be fashioned in accordance with any of several known fabricationmethods. In the preferred embodiment shown in FIG. 1, however, bracket10 is cold-formed from sheet stock. Bracket 10 will preferably be formedwith side edge flanges 14 for increased stiffness, but these are notessential to the invention.

Embedment portion 11 preferably has supplementary anchorage means suchas anchor tab 12, to enhance the strength and security of the bracket'sembedment in a precast panel. As shown in FIG. 1, anchor tab 12 may beformed by cutting or punching the partial outline of anchor tab 12 andbending it back from the main body of embedment portion 11 to a desiredorientation.

Extension portion 13 has an outer end 15, which is preferably formedwith an angled lip 16. A primary fastener opening 30 is provided inextension portion 13 adjacent to outer end 15. In preferred embodiments,an auxiliary fastener opening 32 is also provided, and preferablydisposed between primary fastener opening 30 and embedment portion 11.Extension portion 13 is formed with abutment means, for helping tomaintain an air space of substantially uniform width between precastpanels having mounting brackets 10 and a supporting structure to whichthe panels are mounted (as will be described in greater detail herein).In the embodiment shown in FIG. 1, the abutment means is provided in theform of an angled tab 20 which is cut or punched from the main body ofextension portion 13 and formed in a desired configuration.

The specific physical dimensions of bracket 10 may be varied to suit therequirements of a given application, taking into consideration variousfactors including the dimensions and weight of the cladding panel inwhich bracket 10 is to be cast. To provide only one example, brackets 10approximately 15 mm wide and formed from 24 gauge sheet steel(approximately 0.024 inches or 0.61 millimeters thick) have beensuccessfully used with precast concrete panels measuring up to 460 mmsquare and having an approximate thickness of 15 mm thick.

FIG. 2 illustrates a mounting bracket 110 in accordance with a secondembodiment. Bracket 110 has several features in common with bracket 10,as indicated by the use of common reference numerals. What distinguishesbracket 110, however, is that the abutment means is provided as ashoulder 120 formed integrally with bracket 110. For greater clarity indifferentiating bracket 110 from bracket 10, the embedment portion andextension portion of bracket 110 are indicated by reference numerals 111and 113 respectively, with shoulder 120 forming part of extensionportion 113.

FIG. 3 is an elevation of a typical precast cladding panel 50 formedwith mounting brackets 10 in accordance with the present invention; FIG.4 is an end view (or side view) of the panel of FIG. 3. As illustrated,panel 50 has a front face 52 (which may be flat or textured as desired),a generally planar rear face 54, two longitudinal edges 56 (which may beupper or lower edges, depending on the orientation of panel 50), andside edges 58. As shown in the Figures, panel 50 may be rectilinear inshape, but this is not essential; panel 50 could take other geometricshapes without departing from the present invention. For example, eitheror both of longitudinal edges 56 could be partially or completelycurvilinear. Longitudinal edges 56 and side edges 58 are preferablybeveled as illustrated in the Figures, but this feature is not essentialfor purposes of the present invention; longitudinal edges 56 and sideedges 58 could also be formed at substantially right angles relative tofront face 52 and rear face 54 of panel 50.

In a typical arrangement, as shown in FIG. 3, at least two brackets 10are cast into panel 50 along each of its longitudinal edges 56. As shownin FIG. 4, each bracket 10 extends at an angle rearward and laterallyaway from panel 50, such that each bracket 10 has a maximum rearwardextension distance 62, as measured perpendicular to rear face 54,substantially equal to a desired air space width. By way of exampleonly, an air space of approximately 0.375 inches (10 mm) is commonlyused for cladding panels in residential and light commercialconstruction; other air space widths may be desirable or necessarydepending on specific building requirements.

Brackets 10 may be positioned in a variety of patterns alonglongitudinal edges 56. In the preferred configuration shown in FIG. 3,brackets 10 are in vertical alignment, but they are offset differentdimensions from each of the side edges 58. This is an advantageousarrangement in that it makes panels 50 reversible, as can be best seenfrom FIG. 5, which is a representative elevation of three panels 50arrayed in vertically adjacent fashion. Panels 50 are all the same, butbecause of the reversible orientation of their brackets 10 as describedabove, adjacent panels are simply rotated 180 degrees relative to eachother so that their respective brackets 10 do not interfere.

The specific bracket layouts shown in FIGS. 3 and 5 are exemplary only,and persons skilled in the art of the invention will readily appreciatethat brackets 10 can be arranged in a variety of alternative mannerswithout departing from the present invention. It is not necessary forbrackets 10 to be positioned along longitudinal edges 56 of panels 50 inany particular manner or relationship, provided of course that there isno interference between the brackets 10 of adjacent panels when they aremounted to a support structure.

FIG. 6 is an end view (or side view) of the panel arrangement in FIG. 5,mounted on a vertical support structure 70. As can be seen from FIG. 6,when panels 50 are placed against support structure 70, they create anair space 60 having a substantially uniform width 62, due to therigidity of brackets 10 and the angular orientation at which they arecast into panels 50. FIG. 6 also illustrates how it is only necessary toconnect the uppermost brackets 10 of each panel 50 to support structure70. This feature is illustrated with greater clarity in other Figures,as will now be described in detail.

FIG. 7A is an enlarged detail showing how a typical bracket 10 at anupper longitudinal edge 56 is connected to support structure 70. It canalso be seen from FIG. 7A that bracket 10 is cast into panel 50 suchthat the abutment means (in the form of angled tab 20) is substantiallyin alignment with rear face 54 of panel 50; in other words, angled tab20 is disposed at a distance 62 from the point of maximum rearwardextension of extension portion 13. To mount panel 50 to supportstructure 70, a suitable primary fastener 40 (such as a wood screw, lagscrew, or spike) is driven through primary fastener opening 30 of eachof the brackets 10 along upper longitudinal edge 56 of panel 50, andinto support structure 70.

In the Figures, support structure 70 is conceptually illustrated ascomprising vertical structural members 71 (such as wood or steel studs)with exterior structural sheathing 73 (such as plywood or orientedstrand board) in accordance with well-known construction techniques.This form of construction is particularly compatible with the presentinvention since the structural sheathing 73 will provide a suitablesubstrate to receive primary fasteners 40 regardless of the relativelateral positions of brackets 10 relative to vertical members 71. It istherefore unnecessary for brackets 10 to be in alignment with verticalmembers 71. As will be seen, however, it is not essential to have asupport structure 70 of this specific construction in order to use thepanel mounting brackets of the present invention, and in fact they canbe readily used with support structures 70 that do not have exteriorsheathing, or that have non-structural sheathing (such as foaminsulation panels).

As shown in FIG. 7B, an auxiliary fastener 42 may be driven throughauxiliary fastener opening 32 to provide a more robust structuralconnection. When auxiliary fastener opening 32 is disposed close toembedment portion 11 as shown in FIG. 7A, auxiliary fastener 42 can havethe additional beneficial effect of creating a moment arm that urges thelower longitudinal edge 56 of panel 50 against support structure 70.

FIG. 7C illustrates a connection much the same as in FIG. 7A, exceptthat in this case panel 50 has alternative brackets 110 withintegrally-formed abutment shoulder 120. In a fashion analogous toangled tabs 20 of brackets 10, shoulder 120 is disposed at a distance 62from the point of maximum rearward extension of extension portion 13.Alternative brackets 110 are connected to support structure 70 in thesame manner as brackets 10 in FIGS. 7A and 7B.

FIG. 8A is a section through a typical horizontal field joint betweentwo cladding panels 50 having brackets 10 in accordance with theinvention. For convenient reference in FIG. 8A (and in other Figures),the panel above the horizontal joint is referred to as upper panel 50U,and the panel below the joint is referred to as lower panel 50L.Similarly, the suffix “U” or “L” has been added to the referencenumerals of various panel and bracket features to indicate that they arereferable to upper panel 50U or lower panel 50L (and/or their respectivebrackets 10U and 10L) as the case may be.

At a typical horizontal joint as shown in FIG. 8A, lower panel 50L ismounted to support structure 70 by connecting brackets 10L (disposedalong the upper longitudinal edge 56L of lower panel 50L) to supportstructure 70 as previously described with reference to FIG. 7A (and,optionally, FIG. 7B). Lower panel 50L is thus disposed with its rearface 54L at a distance 62 from the face of support structure 70(creating desired air space 60). Upper panel 50U is then installed bysliding extension portions 13U of brackets 10U (disposed along the lowerlongitudinal edge 56U of upper panel 50U) behind lower panel 50L andinto air space 60, until lower edge 56U of upper panel 50U abuts upperedge 56L of lower panel 50L as shown. Alternatively, upper panel 50U maybe positioned so as to leave a narrow vertical space between upper edge56L and lower edge 56U, if desired. Because of the substantiallyidentical configuration and orientation of brackets 10U and 10L(relative to upper panel 50U and lower panel 50L respectively),extension portions 13U of upper panel 50U will abut support structure70, and angled tabs 20U of brackets 10U will abut rear face 54L of lowerpanel 50L, while rear face 54U of upper panel 50U will abut angled tabs20L of brackets 10L, thus bringing rear faces 54U and 54L intosubstantial alignment. Upper panel 50U may then be physically connectedto support structure 70 as previously described with reference to FIG.7A (and, optionally, FIG. 7B).

Particular advantages of the present invention may be readilyappreciated from the foregoing discussion of FIG. 8A. There is nophysical connection between lower brackets 10L of upper panel 50U andsupport structure 70. Upper panel 50U is effectively locked in lateralposition behind lower panel 50L, so there is no need for additionalmeans to provide lateral stability to the lower portion of upper panel50U. Upper panel 50U preferably rests upon lower panel 50L duringinstallation, thus facilitating both horizontal and vertical alignmentof the panels. Rear panel faces 54U and 54L are automatically broughtinto substantial alignment when upper panel 50U is positioned abovelower panel 50L as described; this is beneficial to facilitaterelatively unimpeded drainage of moisture down the rear faces of thepanels.

Because as few as two brackets 10 can be used along each longitudinaledge 56 of a typical cladding panel 50 (or, for small or narrow panels,only a single bracket 10 on each edge), and since brackets 10 are fairlynarrow in width, brackets 10 present minimal impedance to the movementof moisture within air space 60, whether in either liquid or vapourform.

An additional advantage is obtained in preferred embodiments of bracket10 in which outer end 15 of extension portion 13 is formed with anangled lip 16. As may be appreciated from FIG. 8A, angled lip 16U ofbracket 10U may be configured to act as a drip edge, so that moisturewill drip off of angled lip 16U in approximately the middle of air space60, with the desirable effect of minimizing moisture contact withsupport structure 70.

A further advantage is that the foregoing and other practical benefitsare achieved using the same mounting bracket 10 on both the upper andlower edges of cladding panels 50. As a matter of convenience, allbrackets 10 are preferably fabricated with primary fastener opening 30(and, optionally, auxiliary fastener opening 32), even though inpractice these openings will typically not be required for thosebrackets 10 that will be on lower panel edges. This simplifiesfabrication and ensures that the required fastener openings will bepresent regardless of the orientation of the panels 50.

FIG. 8B illustrates a typical horizontal field joint similar to thatshown in FIG. 8A, but with cladding panels 50U and 50L having brackets110U and 110L in accordance with the alternative embodiment shown inFIG. 2. The integrally-formed shoulders 120U and 120L of brackets 110Uand 110L function is substantially the same fashion as angled tabs 20Uand 20L in FIG. 8A.

FIG. 9 is a sectional detail illustrating a preferred method formounting the uppermost (or top) cladding panel in an assembly ofcladding panels on a building wall, such as below a soffit or eave. Inthe illustrated detail, top panel 50T has brackets 10T along its lowerlongitudinal edge 56T, but requires no brackets 10 along its upper edge.A spacer channel 74 is attached to support structure 70 near the top ofthe wall in conjunction with a cap flashing 75, using flashing fastener44 as shown. Cap flashing 75 is proportioned to allow for a space 75Aabove top panel 50T. Top panel 50T is mounted after the panel below ithas been mounted, by temporarily positioning top panel SOT at an angle(with its lower edge disposed outwardly away from the wall) and slidingits upper edge upward between spacer channel 74 and cap flashing 75,until brackets 10T are above the upper edge of lower panel 50L. Thelower edge of top panel 50T is moved inward and then lowered so that itis supported on the upper edge of lower panel 50L, with cap flashing 75providing lateral support to the upper edge of top panel 50T. Capflashing 75 will have sufficient strength and flexibility to tolerateoutward elastic deformation during the installation of top panel 50T,such that it will spring back to the position shown in FIG. 9 after toppanel 50T has been positioned.

The installation of top panel 50T may be facilitated by folding angledlips 16T of brackets 10T upward as indicated in FIG. 9. This stepreduces the distance that top panel 50T must be raised above lower panel50L in order for brackets 10T to be able to slide behind lower panel50L. At the same time, this allows cap flashing 75 to be somewhatnarrower in width.

Persons skilled in the art will readily appreciate that other methodsfor mounting top panel 50T are possible. For example, top panel 50Tcould have brackets 10 on both longitudinal edges, with the uppermostbrackets mounted to support structure 70 in the same way as for thelower panels, thereby eliminating the need for spacer channel 74, andwith a cap flashing installed if necessary or desired after top panel50T has been mounted. The suitability of this or any other method ofmounting top panel 50T will depend on the specific architectural detailsof the structure in question.

FIG. 10 is a sectional detail illustrating a preferred method formounting the lowermost (or bottom) cladding panel in an assembly ofcladding panels on a building wall. In the illustrated detail, bottompanel 50B has brackets 10B along its upper longitudinal edge 56B, butrequires no brackets 10 along its lower edge. Bottom panel 50B ismounted to support structure 70 before upper panel 50U above it. Aspacer channel 74 is first attached to support structure 70 near thebottom of the wall, using spacer fastener 46 as shown. Preferably, acontinuous or intermittent bead of mastic 76 or other suitable adhesivematerial is deposited on flange 74A of spacer channel 74. Bottom panel50B is then mounted to support structure 70 using primary fastener 40 inthe manner previously described.

Because the center of gravity of bottom panel 50B is disposed at adistance away from the face of support structure 70 (and from the pointat which brackets 10B are connected thereto), the weight of bottom panel50B induces a counterclockwise moment (as viewed in FIG. 10) urging thelower portion of bottom panel 50B against flange 74A of spacer channel74 and the mastic 76 deposited thereon. This gravity-induced moment andmastic 76 both help to maintain the lower portion of bottom panel 50B inlateral position against support structure 70 without need for directmechanical fastening. It can be readily appreciated from FIG. 10 thatthe use of auxiliary fastener 42 in conjunction with brackets 10B willinduce a second counterclockwise moment which enhances the lateralstability of the lower portion of bottom panel 50B against supportstructure 70. For this reason, it is particularly preferable to useauxiliary fasteners 42 when mounting bottom panels 50B in a claddingpanel assembly, especially for exterior installations in which the panelassembly may be subject to outwardly-acting negative pressures (due towind or other factors).

After bottom panels 50B have been mounted, additional panels may bemounted thereabove in the usual manner, as shown in FIG. 10 (forpurposes of which panels immediately above bottom panels 50B arereferenced as upper panels 50U).

Persons skilled in the art will readily appreciate that other methodsfor mounting bottom panel 50B are possible. For example, bottom panel50B could have brackets 10 on both longitudinal edges, therebyeliminating the need for spacer channel 74. In such alternative methods,it may be desirable or necessary to provide an additional flashing orother means for covering or protecting the brackets on the lower edgesof bottom panel 50B. The suitability of this or any other method ofmounting bottom panel 50B will depend on the specific architecturaldetails of the structure in question.

FIG. 11 illustrates how strapping members 80 may be used to facilitatethe mounting of cladding panels having brackets 10 on a supportstructure 70 that incorporates spaced vertical studs 71 but has noexterior structural sheathing. Strapping members 80 are positionedhorizontally across studs 71 and fastened thereto using strappingfasteners 82. As may be seen from FIG. 11, strapping members 80 have asufficient width W so that when positioned straddling intendedhorizontal panel joint locations, they will provide a surface againstwhich the extension portions 13 of brackets 10 can abut, and into whichprimary and auxiliary fasteners 40 and 42 may be driven as required (inlieu of structural sheathing).

In the preferred embodiment shown in FIG. 11 (and in cross-section inFIG. 11A), strapping members 80 are cold-formed channels made fromrust-resistant sheet steel, with closely-spaced perforations tofacilitate installation of fasteners 82, 40, and 42 without need forfield drilling. However, regular dimension lumber (e.g., one-by-threes)or alternative cold-formed metal shapes could be used instead of theillustrated strapping members 80.

Where stud walls are sheathed with exterior foam insulation panels,strapping members 80 may be applied against the exterior faces of thefoam panels, with strapping fasteners 82 passing through the foam panelsbefore engaging studs 71. Where strapping members 80 are channels as inFIGS. 11 and 11A, the channel flanges 80A will be pressed into the foam.

FIG. 12 illustrates how the use of mounting brackets 10 in accordancewith the present invention facilitates compact stacking of claddingpanels 50 on a pallet 84 (or other supporting surface) for purposes ofstorage and shipping. Because of their angular orientation, as well astheir positioning very close to the longitudinal edges of panels 50,brackets 10 present little or no interference with adjacent stackedpanels. Therefore, panels 50 can be stacked with little or no spacebetween them. It will generally be desirable, however, to providecushioning means 86 between panels in a stack, to prevent panel damageduring shipping and handling (especially to the outer panel faces, whichtypically will be exposed to view after installation). The cushioningmeans 86 could be in the form of resilient matting, heavy cardboard,wood lath strips, or other material that will not mar cladding panelsurfaces.

FIGS. 13, 14, and 15 illustrate a preferred forming system for castingcladding panels having brackets 10 in accordance with the presentinvention. Although individual panel forms could be used, it ispreferable and more efficient to use a multi-panel forming frame 90 asshown in FIGS. 13 and 14. Forming frame 90 has multiple casting cells92, typically with two (or more) bracket pockets 94 formed into frame 90in desired positions along opposing edges 93 (corresponding to thelongitudinal edges of the panels 50 to be cast in cells 92). As bestseen in FIG. 15, each bracket pocket 94 has a bearing surface 94A forreceiving angled tab 20 of a typical bracket 10. Bearing surface 94Aalso serves as a casting line guide; i.e., when a casting cell 92 isfilled to the level of bearing surfaces 94A of its corresponding bracketpockets 94, rear face 54 of the resultant precast panel 50 willsubstantially coincide with angled tab 20, thus helping to ensure thatextension portions 13 of brackets 10 will extend perpendicular to rearface 54 a distance 62 corresponding to the desired air space width, aspreviously described.

To facilitate the casting of bracket 10 into panel 50 at a desiredangular orientation, bracket 10 preferably will have an anchor tab 12 aspreviously described, dimensioned and configured such that it will restagainst the inner surface of casting cell 92 so as to help maintainbracket 10 in the desired orientation during the panel castingoperation, with the fluid pressure of the concrete (or other castingmaterial) tending to hold anchor tab 12 in position against the castingcell surface.

As illustrated in FIGS. 14 and 15, the maintenance of the bracketposition during panel casting may be further facilitated by encasingpart of the extension portion 13 of each bracket 10 in a resilient plug96 that helps to hold bracket 10 in the desired angular orientation.This preferred feature may be achieved using a bracket plug mold (notshown) having appropriately shaped casting cells into each of which abracket 10 may be positioned, whereupon the casting cells may be filledwith a suitable liquid compound (e.g., latex or silicone) that will coolor cure to form resilient plug 96 partially encasing extension portion13 as shown in FIG. 15. Brackets 10 with resilient plugs 96 may then bepositioned in bracket pockets 94 as illustrated by way of example withreference to casting cell 92A in FIG. 14. The next step is to fillcasting cells 92 with concrete (or other casting material) to formcladding panels 50 as illustrated in plan view with reference to castingcell 92B in FIG. 14 and in section in FIG. 15. After panels 50 havecured, resilient plugs 96 may be easily pulled off of brackets 10 anddiscarded.

FIGS. 16 and 17 illustrate a third embodiment of the mounting bracket ofthe present invention. As shown in FIG. 16, alternative bracket 210 isformed from metal wire of a gauge suitable to provide the structuralstrength and stiffness required for specific panel applications. Bracket210 has embedment portion 211 and extension portion 213 analogous toembedment portion 11 and extension portion 13 of thepreviously-described bracket 10. Bracket 210 is twist-formed to create afastener opening 30 analogous to that of bracket 10, and to formabutment means in the form of a shoulder 220 analogous to shoulder 120of alternative bracket 110.

It will be readily appreciated by those skilled in the art that variousmodifications of the present invention may be devised without departingfrom the essential concept of the invention, and all such modificationsare intended to be included in the scope of the claims appended hereto.

In this patent document, the word “comprising” is used in itsnon-limiting sense to mean that items following that word are included,but items not specifically mentioned are not excluded. A reference to anelement by the indefinite article “a” does not exclude the possibilitythat more than one of the element is present, unless the context clearlyrequires that there be one and only one such element.

1. A mounting bracket for partial embedment in a precast panel having afront face, a generally planar rear face, an upper edge, and a loweredge, said bracket comprising: (a) a rigid, elongate main body having anouter side, an inner side, and two longitudinal edges, said main bodyalso defining: a.1 an embedment portion; and a.2 an extension portioncontiguous with the embedment portion, said extension portion having aninner end; and (b) abutment means associated with the outer side of theextension portion, said abutment means having an outer edge; whereinwhen the embedment portion is embedded in a precast panel such that theextension portion projects from the rear face of the panel so as to forman obtuse angle between the inner side of the extension portion and therear face of the panel, the outer edge of the abutment means willsubstantially coincide with the plane of the rear face of the panel. 2.The mounting bracket of claim 1 wherein the extension portion has aprimary fastener opening near its inner end.
 3. The mounting bracket ofclaim 2 wherein the extension portion has an auxiliary fastener openingpositioned away from the primary fastener opening and toward theembedment section.
 4. The mounting bracket of claim 1, furthercomprising an auxiliary anchorage element associated with the embedmentportion.
 5. The mounting bracket of claim 1 wherein the bracket isformed from sheet metal.
 6. The mounting bracket of claim 5 wherein theabutment means is a punch-formed angled tab.
 7. The mounting bracket ofclaim 4 wherein the bracket is formed from sheet metal and the auxiliaryanchorage element main body is a punch-formed anchor tab.
 8. Themounting bracket of claim 1, further comprising a stiffening flangeextending from one of the longitudinal edges of the main body
 9. Themounting bracket of claim 5 wherein the abutment means is formedintegrally with the main body.
 10. The mounting bracket of claim 1wherein the bracket is formed from metal wire.
 11. A precast panelhaving a front face, a generally planar rear face, an upper edge, and alower edge, and further having at least two mounting brackets embeddedin spaced-apart relation adjacent a selected one of said upper and loweredges of the panel, each said mounting bracket comprising: (a) a rigid,elongate main body having an outer side, an inner side, and twolongitudinal edges, said main body also defining: a.1 an embedmentportion; and a.2 an extension portion contiguous with the embedmentportion, said extension portion having an inner end; and (b) abutmentmeans associated with the outer side of the extension portion, saidabutment means having an outer edge; wherein the embedment portion ofeach mounting bracket is embedded in the panel such that: (c) theextension portion projects from the rear face of the panel so as to forman obtuse angle between the inner side of the extension portion and therear face of the panel; (d) the outer edge of the abutment meanssubstantially coincides with the plane of the rear face of the panel;and (e) at least a portion of the abutment means is disposed outboard ofthe associated panel edge; and wherein the outer edges of the abutmentmeans of each bracket is disposed at a substantially uniform distancefrom the inner ends of their corresponding extension portions, asmeasured perpendicular to the plane of the rear face of the panel. 12.The precast panel of claim 11, wherein each mounting bracket has atleast one fastener opening near the inner end of its extension portion.13. The precast panel of claim 11, having at least two mounting bracketsembedded in spaced-apart relation adjacent its upper edge and at leasttwo mounting brackets embedded in spaced-apart relation adjacent itslower edge, wherein each mounting bracket embedded adjacent the upperpanel edge has at least one fastener opening near the inner end of itsextension portion.
 14. The precast panel of claim 11 wherein theextension portion of each mounting bracket has a primary fasteneropening near its inner end.
 15. The precast panel of claim 14 whereinthe extension portion of each mounting bracket has an auxiliary fasteneropening positioned away from the primary fastener opening and toward theembedment section.
 16. The precast panel of claim 11 wherein eachmounting bracket further comprises an auxiliary anchorage elementassociated with the embedment portion.
 17. The precast panel of claim 11wherein each mounting bracket is formed from sheet metal.
 18. Theprecast panel of claim 17 wherein the abutment means of each mountingbracket is a punch-formed angled tab.
 19. The precast panel of claim 16wherein each mounting bracket is formed from sheet metal and theauxiliary anchorage element is a punch-formed anchor tab.
 20. Theprecast panel of claim 11 wherein each mounting bracket furthercomprises a stiffening flange extending from one of the longitudinaledges of the main body
 21. The precast panel of claim 17 wherein theabutment means of each mounting bracket is formed integrally with themain body.
 22. The precast panel of claim 11 wherein each mountingbracket is formed from metal wire.